| From: | John A Meinel <john(at)arbash-meinel(dot)com> |
|---|---|
| To: | Joost Kraaijeveld <J(dot)Kraaijeveld(at)Askesis(dot)nl> |
| Cc: | "Pgsql-Performance (E-mail)" <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: What is the number of rows in explain? |
| Date: | 2005-03-11 14:43:45 |
| Message-ID: | 4231AEA1.7070300@arbash-meinel.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
Joost Kraaijeveld wrote:
>Hi all,
>
>Is the number of rows in explain the number of rows that is expected to be visited or retrieved?
>
>Groeten,
>
>Joost Kraaijeveld
>Askesis B.V.
>Molukkenstraat 14
>6524NB Nijmegen
>tel: 024-3888063 / 06-51855277
>fax: 024-3608416
>e-mail: J(dot)Kraaijeveld(at)Askesis(dot)nl
>web: www.askesis.nl
>
>---------------------------(end of broadcast)---------------------------
>TIP 1: subscribe and unsubscribe commands go to majordomo(at)postgresql(dot)org
>
>
In general, it is the number of rows expected to be retrieved. Since a
Sequential Scan always visits every row, but the rows= number is after
filtering.
John
=:->
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Jacques Caron | 2005-03-11 15:40:49 | Performance tuning |
| Previous Message | Daniel Schuchardt | 2005-03-11 14:27:46 | Re: cpu_tuple_cost |